This invention relates to apparatus for cleaning a filter which is adapted to extract contaminants from a liquid.
More particularly, the invention relates to apparatus for cleaning a swimming pool filter and specifically a filter of the same general type as sold by Hayward Manufacturing Company, Inc. of Elizabeth, N.J. under the trademark PERFLEX. Such a filter comprises an upright vessel having a plurality of porous filter tubes whose lower ends are spaced upwardly from the bottom of the vessel. The tubes are coated with diatomite earth filter powder which removes contaminants from the pool water as the water flows through the tubes. A drain valve is located adjacent the lower end of the vessel and may be selectively opened in order to drain contaminants from the vessel.
Eventually, accumulated contaminants will clog the filter tubes and will cause the filter pressure to rise and the flow to diminish. It then becomes necessary to clean the tubes in order to restore the filter to efficient operation. In a PERFLEX filter of the type described above, cleaning of the tubes is achieved by a "bump" method. That is, the bank of filter tubes is repeatedly raised upwardly and then jarred downwardly in order to shake contaminants off of the tubes.
In many instances, however, the so-called bump method does not effectively clean the tubes. If the algae and bacteria content of the pool water is high, the algae and bacteria tend to "grow" in the diatonic earth powder and tend to cling to the tubes so as to resist being dislodged from the tubes by shaking.